Cutting tools comprising cemented carbide bodies have been used in both coated and uncoated conditions for machining various metals and alloys. Increasing cutting tool resistance to wear and failure modes, including thermal deformation, fracture and chipping, remains an intense area of research and development. To that end, significant resources have been assigned to the development of wear resistant refractory coatings for cutting tools. TiC, TiCN, TiOCN, TiN and Al2O3, for example, have been applied to cemented carbides by chemical vapor deposition (CVD) as well as physical vapor deposition (PVD).
Moreover, the properties of the underlying cutting tool substrate have been investigated. Cutting tool manufacturers have examined compositional changes to cemented carbide bodies and the resulting effects on cemented carbide properties including, but not limited to, hardness, wear resistance, thermal deformation resistance, toughness, density and various magnetic properties. Enhancement of one cemented carbide property, however, often results in the concomitant deterioration of another cemented carbide property. For example, increasing the resistance of a cemented carbide body to deformation can result in decreased toughness and thermal conductivity of the body. Japanese patent application publication JP 2002-356734A recognizes such a problem and describes a cemented carbide body having plastic deformation resistance and increased hardness and thermal conductivity. According to JP 2002-356734A, these objectives are achieved by incorporating into the cemented carbide body several differing solid solution phases of carbides, nitrides and carbonitrides of metals selected from Groups IVB, VB and VIB.
Nevertheless, improvements to cemented carbide substrates are necessary to meet the evolving demands of metal working applications, and a careful balance between competing properties is required when making compositional changes to cemented carbide bodies in efforts to provide cutting tools with improved performance.